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Lizards, Ticks, and Lyme Disease

Lizards are a primary host for nymphal Ixodes pacificus ticks.  Engorged tick nymphs can often be seen attached to the neck area of lizards caught in the wild. 

Some lizards such as the Western Fence lizard and the Southern Alligator lizard may combat risk of Lyme disease in an area because a protein within the lizard blood will kill the infectious bacteria Borrelia burgdorferi in the tick (1).  After the tick nymph is done feeding, it is cleared of the bacteria and cannot transmit the bacteria while it feeds as an adult.  There is speculation that this may be one reason that Lyme disease is much less prevalent on the west coast than the east coast of the United States where the lizard species lack the protein.

However, like most things in's complicated. For example, a study published in 2022 showed that ticks that fed on lizards (instead of mice) were more likely to become infected when next feeding on a mouse infected with Borrelia burdorferi. (2)

Ticks and lizards are so associated with each other that removing lizards from an area can lead to a drastic drop in tick population as well, according to a 2011 study by Swei et al. (3)



1. Lane RS,  Quist GB. 1998. Borreliacidal factor in the blood of the Western Fence Lizard (Sceloporus occidentalis).” Journal of Parasitology 84(1): 29-34. (behind a paywall)

2. Ring K, Couper LI, Sapiro AL, Yarza F, Yang XF, Clay K, Mateusiak C, Chou S, Swei A. 2022. Host blood meal identity modifies vector gene expression and competency. Molecular Ecology 31: 2698-2711. DOI:

3. Swei A, Briggs CJ, Lane RS, Ostfeld RS. 2011. Impact of lizard removal on the abundance and infection prevalence of a Lyme disease vector. Proceedings of the Royal Society B 278(1720): 2970-2978. DOI:



Page last reviewed: November 16, 2023

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